The present invention generally relates to the field of cooling systems. More specifically, it relates to efficient fluid cooling systems and a method for their operation.
Various types of cooling systems are available commercially. Examples of these cooling systems include, but are not limited to, vapor compression systems and thermoelectric cooling systems. Conventional vapor compression systems use chlorofluorocarbons (CFC) refrigerants such as Freon, hydrochloroflurocarbon (HCFC) refrigerants such as R134, or hydrofluorocarbons (HFC) refrigerants such as R410 for cooling purposes. However, the use of CFC refrigerants is being phased out because they pose a threat to the environment. The CFC refrigerants, when exposed to the atmosphere, cause depletion in the ozone layer. This is a major threat to the environment, since the absence of the ozone layer increases the amount of ultraviolet radiation on the earth, which in turn may affect the health of humans and animals. Further, these refrigerants (CFC, HCFC and HFC) contribute to global warming by absorbing infrared radiation. In fact, they can absorb about 1,000 to 2,000 times more infrared radiation than carbon dioxide. In addition to being a potential threat to the environment, the vapor compression systems using these refrigerants are heavy, create noise, and vibrate when in use.
Thermoelectric cooling systems are reliable, lightweight, and an environment-friendly alternative to traditional vapor compression systems. Conventional thermoelectric cooling systems use one or more thermoelectric couples in conjunction with a DC power source. When these thermoelectric cooling systems are switched off, heat flows through the thermoelectric couples, thereby warming the cooled chamber to ambient temperature. As a result, to maintain a cold chamber at a desired temperature, conventional thermoelectric cooling systems need to be switched on for long intervals of time, which increases power consumption. Thus, conventional thermoelectric cooling systems are inefficient for cold storage purposes.
In the last decade, efforts made to increase the coefficient of performance (COP) of the thermoelectric devices included using improved materials, such as nano-structured bismuth telluride bulk materials, in the thermoelectric devices. However, the improved COP of the thermoelectric devices using such improved materials is limited to less than one at room temperature. Another attempt to increase the COP included methods for reducing the temperature differential across the thermoelectric devices by using improved heat exchangers and properly optimized currents. These methods also have limited COP enhancements and all the advantages are lost when steady-state temperatures are attained. Therefore, the performance of the thermoelectric cooling systems is still not as efficient as that of the vapor compression refrigeration systems.
Improved devices are required that can regulate heat flow through the thermoelectric couples efficiently.
Accordingly, there is a need for a power-efficient and eco-friendly cooling system.